Idk if its a language barrier or what, but people have given you multiple reasons why you have low dps and there have multiple people trying to help you. You just don't understand that you are doing multiple things wrong. Fixing your dps just doesn't instantly happen. And it's generally not just one reason why it's low.
its very simple, dont go for full haste over intel until you hit 505 ilvl or more. But at 499 ilvl there should be no problem reaching 8085 haste. Again, elegon trinket is a must over yulon, if you dont have it and there is no way to reach the 8085 barrier without it then thats that. Ill check your logs again to see what you could improve but all seems good to me. Again, the others are doing more because they use the flight to get the damage buff.
Ok so here is smthn you can improve. You have 12 dp casts and 68 ticks of insanity. If you squeeze in at least 3 mind flays on each dp, that should be 9 ticks per dp. Also at heroism and with pi with some clipping you should maybe get 4, altho you might not have the haste for it so lets say 3 mind flays per dp x 3 ticks should be 9 ticks per each dp. You should have 9x12 108 ticks of insanity if im not entirely miscalculating you have way less than that. After you get the 3rd orb with mb and use the dp maximum prio is on insanity, you should get them up until mb is off cooldown. So if you are redotting or whatever, stop it and get full insanity use from those 6 seconds and it will boost your single target alot. You have 50 seconds of insanity uptime on 72 seconds of dp uptime, so you are basically wasting 22 seconds somehow. Maybe winds maybe bad spell priorities, that shouldnt happen.
Minimalize movement, try to predict and use DP,SW, DS or halo during required movement.
I realized this when i first met priest with same gear doing much more dps. On recount we could see big differecne between number of ticks. Why? Halion ... he stayed very close to boss and only had to do 2 step sto run throught him, refreshing sw during that... I simply lost 2-3 gcd's doing nothing, while running big distances every time boss threw fire on me.
It's only think u have to care about after u learn priest's simple rotation, and reforge your gear around mr.robot or so:
Spend every second on raid casting as strong spell as you can.